Doug / smarc-fsl-linux-kernel

Download as
Browse Code ยป

Commit 6932078376e2c1fd49b6c4aa41cc5e162ee83d8a

Authored by Stephen Boyd
Committed by Rafael J. Wysocki
1 parent c4afc41094
Exists in smarc-imx_3.14.28_1.0.0_ga and in 1 other branch imx_3.14.28_1.0.0_ga

cpufreq: Don't use smp_processor_id() in preemptible context 

Workqueues are preemptible even if works are queued on them with
queue_work_on(). Let's use raw_smp_processor_id() here to silence
the warning.

BUG: using smp_processor_id() in preemptible [00000000] code: kworker/3:2/674
caller is gov_queue_work+0x28/0xb0
CPU: 0 PID: 674 Comm: kworker/3:2 Tainted: G        W    3.10.0 #30
Workqueue: events od_dbs_timer
[<c010c178>] (unwind_backtrace+0x0/0x11c) from [<c0109dec>] (show_stack+0x10/0x14)
[<c0109dec>] (show_stack+0x10/0x14) from [<c03885a4>] (debug_smp_processor_id+0xbc/0xf0)
[<c03885a4>] (debug_smp_processor_id+0xbc/0xf0) from [<c0635864>] (gov_queue_work+0x28/0xb0)
[<c0635864>] (gov_queue_work+0x28/0xb0) from [<c0635618>] (od_dbs_timer+0x108/0x134)
[<c0635618>] (od_dbs_timer+0x108/0x134) from [<c01aa8f8>] (process_one_work+0x25c/0x444)
[<c01aa8f8>] (process_one_work+0x25c/0x444) from [<c01aaf88>] (worker_thread+0x200/0x344)
[<c01aaf88>] (worker_thread+0x200/0x344) from [<c01b03bc>] (kthread+0xa0/0xb0)
[<c01b03bc>] (kthread+0xa0/0xb0) from [<c01061b8>] (ret_from_fork+0x14/0x3c)

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Showing 1 changed file with 8 additions and 1 deletions Side-by-side Diff

drivers/cpufreq/cpufreq_governor.c
Diff comments   View file @ 6932078
... ... @@ -123,7 +123,14 @@
123 123 return;
124 124  
125 125 if (!all_cpus) {
126   - __gov_queue_work(smp_processor_id(), dbs_data, delay);
  126 + /*
  127 + * Use raw_smp_processor_id() to avoid preemptible warnings.
  128 + * We know that this is only called with all_cpus == false from
  129 + * works that have been queued with *_work_on() functions and
  130 + * those works are canceled during CPU_DOWN_PREPARE so they
  131 + * can't possibly run on any other CPU.
  132 + */
  133 + __gov_queue_work(raw_smp_processor_id(), dbs_data, delay);
127 134 } else {
128 135 for_each_cpu(i, policy->cpus)
129 136 __gov_queue_work(i, dbs_data, delay);